vmThread.hpp revision 11020:c0ea2e3ebe83
1/* 2 * Copyright (c) 1998, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#ifndef SHARE_VM_RUNTIME_VMTHREAD_HPP 26#define SHARE_VM_RUNTIME_VMTHREAD_HPP 27 28#include "runtime/perfData.hpp" 29#include "runtime/thread.hpp" 30#include "runtime/vm_operations.hpp" 31 32// 33// Prioritized queue of VM operations. 34// 35// Encapsulates both queue management and 36// and priority policy 37// 38class VMOperationQueue : public CHeapObj<mtInternal> { 39 private: 40 enum Priorities { 41 SafepointPriority, // Highest priority (operation executed at a safepoint) 42 MediumPriority, // Medium priority 43 nof_priorities 44 }; 45 46 // We maintain a doubled linked list, with explicit count. 47 int _queue_length[nof_priorities]; 48 int _queue_counter; 49 VM_Operation* _queue [nof_priorities]; 50 // we also allow the vmThread to register the ops it has drained so we 51 // can scan them from oops_do 52 VM_Operation* _drain_list; 53 54 // Double-linked non-empty list insert. 55 void insert(VM_Operation* q,VM_Operation* n); 56 void unlink(VM_Operation* q); 57 58 // Basic queue manipulation 59 bool queue_empty (int prio); 60 void queue_add_front (int prio, VM_Operation *op); 61 void queue_add_back (int prio, VM_Operation *op); 62 VM_Operation* queue_remove_front(int prio); 63 void queue_oops_do(int queue, OopClosure* f); 64 void drain_list_oops_do(OopClosure* f); 65 VM_Operation* queue_drain(int prio); 66 // lock-free query: may return the wrong answer but must not break 67 bool queue_peek(int prio) { return _queue_length[prio] > 0; } 68 69 public: 70 VMOperationQueue(); 71 72 // Highlevel operations. Encapsulates policy 73 bool add(VM_Operation *op); 74 VM_Operation* remove_next(); // Returns next or null 75 VM_Operation* remove_next_at_safepoint_priority() { return queue_remove_front(SafepointPriority); } 76 VM_Operation* drain_at_safepoint_priority() { return queue_drain(SafepointPriority); } 77 void set_drain_list(VM_Operation* list) { _drain_list = list; } 78 bool peek_at_safepoint_priority() { return queue_peek(SafepointPriority); } 79 80 // GC support 81 void oops_do(OopClosure* f); 82 83 void verify_queue(int prio) PRODUCT_RETURN; 84}; 85 86 87// 88// A single VMThread (the primordial thread) spawns all other threads 89// and is itself used by other threads to offload heavy vm operations 90// like scavenge, garbage_collect etc. 91// 92 93class VMThread: public NamedThread { 94 private: 95 static ThreadPriority _current_priority; 96 97 static bool _should_terminate; 98 static bool _terminated; 99 static Monitor * _terminate_lock; 100 static PerfCounter* _perf_accumulated_vm_operation_time; 101 102 void evaluate_operation(VM_Operation* op); 103 public: 104 // Constructor 105 VMThread(); 106 107 // Tester 108 bool is_VM_thread() const { return true; } 109 bool is_GC_thread() const { return true; } 110 111 // The ever running loop for the VMThread 112 void loop(); 113 114 // Called to stop the VM thread 115 static void wait_for_vm_thread_exit(); 116 static bool should_terminate() { return _should_terminate; } 117 static bool is_terminated() { return _terminated == true; } 118 119 // Execution of vm operation 120 static void execute(VM_Operation* op); 121 122 // Returns the current vm operation if any. 123 static VM_Operation* vm_operation() { return _cur_vm_operation; } 124 125 // Returns the single instance of VMThread. 126 static VMThread* vm_thread() { return _vm_thread; } 127 128 // GC support 129 void oops_do(OopClosure* f, CodeBlobClosure* cf); 130 131 void verify(); 132 133 // Performance measurement 134 static PerfCounter* perf_accumulated_vm_operation_time() { return _perf_accumulated_vm_operation_time; } 135 136 // Entry for starting vm thread 137 virtual void run(); 138 139 // Creations/Destructions 140 static void create(); 141 static void destroy(); 142 143 private: 144 // VM_Operation support 145 static VM_Operation* _cur_vm_operation; // Current VM operation 146 static VMOperationQueue* _vm_queue; // Queue (w/ policy) of VM operations 147 148 // Pointer to single-instance of VM thread 149 static VMThread* _vm_thread; 150}; 151 152#endif // SHARE_VM_RUNTIME_VMTHREAD_HPP 153